Deployable structures are used in various applications when the physical size of an apparatus needs to be temporarily reduced, for example for storage or transportation purposes. One such field in which deployable structures are widely used is that of space-based applications, particularly satellites and other space vehicles which are launched into space in the rocket fairing. Since there is only limited space available in the fairing, deployable structures are used which can be stowed into a small volume prior to launch.
Deployable masts have been developed in which long rigid mast sections are joined by tape-spring hinges. Such masts can be stowed by buckling the tape-spring hinges so that the rigid mast sections are folded back to lie alongside one another. The tape-spring hinges store elastic strain energy that causes the structure to automatically deploy once a restraining force is removed. Whilst this folding arrangement reduces the overall length of the structure in comparison to the length of the fully-deployed mast, the total reduction in size is limited by the length of the rigid mast sections. For example, if the mast comprises three rigid sections of equal length connected by tape-spring hinges, the total length of the collapsed structure will be roughly one-third that of the fully-extended structure. It would therefore be desirable to provide a more compact form of deployable mast structure.
The invention is made in this context.